When the dawn of the second day came one of the angels appeared in the shape of a man. Jacob began to wrestle with him. They were neck and neck until the angel injured his thigh and Jacob became lame. When the day was breaking, the angel said to him: 'What is your name?" He answered: "Jacob." The angel said : "After today you shall not be called (anything) but Israel." Jacob asked: "And who are you? What is your name?" He vanished. Then Jacob knew that he was one of the angels. Jacob was lame, and for this reason the children of Israel do not eat the thigh muscle on the hip socket.